Manchester's most notorious unsolved gang murder cases could be cracked if witnesses broke the walls of silence, according to a top cop.

 Det Chief Supt Darren Shenton, head of GMP’s serious crime division, believes the local community holds the key to bringing killers to justice. There are 22 unsolved murders in Greater Manchester that are thought to be gang-related – and Mr Shenton said that all of them could be solved. These include high-profile cases, such as that of innocent schoolboy Jessie James, 15, who was shot as he cycled through a Moss Side park in September 2006 and hard-working Halton McCollin, 20, killed in a Stretford takeaway in January 2008. Guns and gangs in Manchester: Victims of a sad cycle of revenge... Mr Shenton said: "The key to all of the unsolved murders lies within the community. Every single one of those murders is capable of being solved if people stood up and did the right thing. "In a number of cases we believe we know the circumstances of how somebody has been murdered but have not been able to transfer that into evidence. "There are people within the community who hold the key to unlocking justice and providing families who have lost loved ones in the most tragic of ways with answers. "My appeal would be that if there are people out there who have information about any of the cases to contact us – they can bring the killers to justice. We will receive that information and treat it in confidence. We can protect witnesses at court using special measures and we have a host of ways of giving absolute protection." Despite some murders remaining unsolved, police have made big strides towards ridding the streets of gun crime. Almost six years have passed since anyone was shot dead in Moss Side, the neighbourhood historically most troubled by gangs, and there have been no gang-related murders in the city of Manchester for more than three years. Detectives credit their success to improved police responses and community efforts to steer young people away from trouble. Gun crime in Greater Manchester is down year-on-year since 2007 when there were 146 recorded shootings. It fell to just 39 last year – the biggest reduction made by any police force in Britain. Mr Shenton added: "Back in 2006-2007 we made a commitment to the communities of Manchester that we would commit resources to tackling gun and gang crime in the area, reflecting the concerns of the community, and we aimed for gun free streets. We have continued that activity, coupled with working with multi-agency partners and giving people the chance to get away from that lifestyle. We’ve made efforts to talk to parents to given them support to lead their children away from that gun crime and culture. "A number of families have been robbed of their young people and lives have been lost. As police, we’ve been to too many funerals not to be affected by it. Mr Shenton said that there had been a ‘sea change’ in community relations with police that had helped officers to solve murders like that of Giuseppe Gregory, who was gunned down outside the Robin Hood pub in Stretford in May 2009. Three men – Moses Mathias, Njabulo Ndlovu and Hiruy Zerihun – have since been jailed for life after being convicted of his murder. He said: "We have seen a sea change in the community understanding what we are doing. The example is Giuseppe Gregory and Jessie James. Within a very short time members of the community who recognised we were in a different era had provided information. "We absolutely know we will not solve everything in a couple of years but we are committed to working with the community to try to deliver our aim of gun free streets in Greater Manchester."